Public utilities approved rate annualized refund.

No definition available.

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- Definition

Public Utilities, Approved Rate Increase (Decrease), Annualized Revenue

+ References

No definition available.

+ Details

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- Definition

Public utility after-tax total rate of return, infrastructure system replacement surcharge.

+ References

No definition available.

+ Details

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- Definition

Public utility rate base amount.

+ References

No definition available.

+ Details

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- Definition

Regulatory asset percentage change of tariff

+ References

No definition available.

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- Definition

Amount of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Amount of public utility's amended requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

+ Details

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- Definition

Amount of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

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- Definition

Remaining recovery period of regulatory assets for which no return on investment during recovery period is provided, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 340
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478742/980-340-50-1

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-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 55
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478098/980-340-55-2

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Regulatory Matters - Additional Information (Details) - USD ($) $ in Millions										1 Months Ended	3 Months Ended
	Jul. 10, 2025	May 14, 2025	Apr. 17, 2025	Jan. 01, 2025	Dec. 04, 2024	Dec. 01, 2024	Nov. 25, 2024	Jan. 01, 2024	Dec. 13, 2023	Feb. 28, 2025	Dec. 31, 2024	Jun. 30, 2025	Nov. 15, 2024
Spire Alabama Inc [Member] \| Alabama Public Service Commission [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate, increase (decrease) annualized revenue								$ 14.3			$ (4.1)
Public utilities approved rate annualized refund						$ 4.0
Spire Gulf [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate, increase (decrease) annualized revenue					$ 1.3				$ 2.7
Spire Mississippi [Member] \| Missouri Public Service Commission [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate, increase (decrease) annualized revenue				$ 0.6				$ 1.0
Spire Missouri [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory asset, percentage change of tariff													30.00%
Public utilities, request rate increase (decrease), amount										$ 137.4
Public utility rate base amount							$ 4,379.6
Public utility after-tax total rate of return, infrastructure system replacement surcharge							7.05%
Public utilities, requested rate increase (decrease), amount			$ 19.0
Public utilities, approved rate, increase (decrease) annualized revenue		$ 72.6
Spire Missouri [Member] \| Subsequent Event [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount	$ 210.0
Spire Missouri [Member] \| Infrastructure System Replacement Surcharge [Member]
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount										$ 72.6
Future Income Taxes Due From Customers and Pension and Other Postretirement Benefit Costs [Member]
Public Utilities, General Disclosures [Line Items]
Remaining recovery period of regulatory assets for which no return on investment during recovery period is provided (Year)												20 years
PGA Assets [Member]
Public Utilities, General Disclosures [Line Items]
Remaining recovery period of regulatory assets for which no return on investment during recovery period is provided (Year)												1 year
PGA Assets Not Earning a Return [Member]
Public Utilities, General Disclosures [Line Items]
Remaining recovery period of regulatory assets for which no return on investment during recovery period is provided (Year)												15 years